Senior Software Engineer: CTLIMS Modernization & AI-Driven Dev

LE002 Onterris Payroll, LLC; Little Rock (AR); On-site; USD 200,000 - 210,000; Full time

Job summary

Onterris is seeking a senior software engineer to modernize CTLIMS, our Laboratory Information Management System, connecting to Workday in real time. You will lead spec-first development, write Markdown specs and architecture-as-code, and advance test-driven delivery across cloud and hybrid environments.

You will mentor teams, document legacy modules, and build data-flow diagrams while shaping the Azure landing zone.

Qualifications

• 7+ years of professional software engineering experience.
• Strong cloud-native engineering fundamentals (Azure preferred; AWS or GCP acceptable).
• Demonstrated practice with Spec-Driven and Test-Driven Development, clean architecture, and domain-driven design.
• Hands-on experience with AI-assisted development tools (Cursor, ClaudeCode, GitHubCopilot, or similar).
• Ability to read, reverse-engineer, and reason about an unfamiliar or legacy codebase.
• Comfortable producing documentation and diagrams as code (Markdown, Mermaid.js) versioned in Git.
• Strong communication skills; can explain the “why” to experienced engineers and partner effectively across teams.

Responsibilities

• Build through Spec-Driven Development; author Markdown specifications and architecture-as-code with Mermaid.js, commit to Git.
• Establish spec-first development templates and review habits.
• Deliver test-first development (TDD); build automated test coverage to enable fast, confident releases.
• Maintain coverage standards, especially for AI-generated code.
• Implement architectural guardrails to keep modular boundaries and prevent monolith erosion.
• Use AI tools (Cursor, ClaudeCode) for codebase archaeology, documentation and prototyping; contribute to .cursorrules and prompt libraries.
• Reverse-engineer and document legacy system modules: purpose, inputs, outputs, dependencies, data models, and technical debt.
• Create data-flow diagrams for sample lifecycles, Workday integration, billing triggers, instrument interfaces, and authentication/authorization.
• Contribute to integration inventory and technical-debt register, triaging components as Fix Now, Doc, Defer, or Accept Risk.
• Shape CTLIMS placement within our Azure landing zone and environment tiers (production, non-production, sandbox); support high-availability and hybrid on-prem design.
• Work with Staff Engineer, cloud landing-zone owner, and platform architects to align modernization with existing Onterris platforms.
• Develop reference implementations and prototypes to de-risk architecture choices.
• Help the team move from “ready to start” to shipping without a standing start, assuming modernization is approved.

Skills

Cloud-native engineering

Spec-Driven Development

Test-Driven Development

AI-assisted development tools

Legacy system understanding

Documentation as code

Cross-team communication

Tools

Azure

Git

Mermaid.js

Podman

Docker

Workday integration

Job description

Onterris is seeking a senior software engineer to modernize CTLIMS, our Laboratory Information Management System, connecting to Workday in real time. You will lead spec-first development, write Markdown specs and architecture-as-code, and advance test-driven delivery across cloud and hybrid environments.

You will mentor teams, document legacy modules, and build data-flow diagrams while shaping the Azure landing zone.